FDA approves avapritinib for advanced systemic mastocytosis

17 Jun 2021
FDA approves avapritinib for advanced systemic mastocytosis

The Food and Drug Administration approved avapritinib for adult patients with advanced systemic mastocytosis, including patients with aggressive systemic mastocytosis (ASM), systemic mastocytosis with an associated haematological neoplasm (SM-AHN), and mast cell leukaemia (MCL).

Efficacy was evaluated in EXPLORER (NCT02561988) and PATHFINDER (NCT03580655), two multi-centre, single-arm, open-label clinical trials enrolling patients with AdvSM.

The main efficacy outcome measure was overall response rate (ORR) per modified IWG-MRT-ECNM criteria, as adjudicated by a central committee. Additional efficacy measures were duration of response (DOR), time to response, and changes in individual measures of mast cell burden. Fifty-three patients received daily doses of avapritinib, up to 200 mg.

The ORR in all evaluable patients in both trials combined was 57% (95% CI: 42, 70) (n=53), with 28% complete remissions and 28% partial remissions. The median duration of response was 38.3 months (95% confidence interval: 19, not estimable) and the median time to response was 2.1 months.

The most common adverse reactions (incidence ≥ 20%) in patients with AdvSM were oedema, diarrhoea, nausea, and fatigue/asthenia.

Avapritinib is not recommended for the treatment of patients with AdvSM with platelet counts of less than 50 X 109/L.

The recommended avapritinib dose is 200 mg orally once daily for patients with AdvSM.

View full prescribing information for avapritinib here.

Source: FDA